McIlroy and Lowry play on the PGA Tour.
Jonathan Caldwell begins his first round shortly at the European Tour's Andalucia Masters.
He's out from just before 1pm, with the early lead at Valderrama held by Julien Gurrier on four-under-par.
Rory McIlroy and Shane Lowry tee off in their first round at the CJ Cup on the PGA Tour later.
Lowry is out from 20-past-4 Irish time alongside Stewart Cink and Marc Leishman.
McIlroy begins from 25-past-5 with defending champion Jason Kokrak and Justin Thomas.